We have to change the terminology; according to scientists who attended the International Climate Change Congress in Copenhagen, the phrases “climate change” and “global warming” need to be retooled to better represent the stark reality that we are now facing. A climate catastrophe — or climate breakdown — would seem to be better choices for what the world will endure over the next 90 years.

Scientists now suggest that just 2° C (3.6° F) of warming could trigger bacterial growth in the arctic permafrost and release billions of tons of CO2 and methane, creating a terrible feedback loop in which warming creates more warming.

A rise of 4°C (7.2° F) will eliminate more than 85 percent of the Amazon rainforest by killing trees which are highly susceptible to small changes in temperature, creating yet another massive carbon time bomb. What’s particularly frightening about this study — conducted by researchers at the Met Office Hadley Centre — is that the death of the rainforest has the potential to alter regional weather patterns in ways that researchers simply cannot predict.

The scientists at the congress are worried that politicians are reading from a hopelessly out-of-date policy paper: the IPCC Fourth Assessment Report. To drive home their urgent message, researchers are describing a 5° C world that will be wracked by floods, droughts, severe hurricanes, cyclones and typhoons, and desperate heat waves. The oceans will become far less productive, the corals will die, and extinction will take more than 50 percent of species.

Professor John Schellnuber of the Potsdam Institute for Climate Impact Research still believes that we can limit global warming to manageable levels, but he lays out an ambitious roadmap that would require global cooperation and generosity of spirit. He suggests that a wide-reaching international deal would need to greatly expand environmentally protected areas; create a global emissions trading scheme that would benefit poorer countries; and develop at least 12 climate change Apollo Projects — such as a super solar thermal plants in the Sahara — that would have potential to usher in a new era of clean, renewable energy.

If we fail to agree to cut global emissions by 80 percent by 2050 — far above the 50 percent global target currently bandied about — then Schellnuber says we’re playing Russian Roulette, and five of the barrels are loaded.